On Monday afternoon Bernie Sanders showed us how he could win the Democratic nomination.

Appearing at a pseudo-town hall event on Fox News, Sanders argued in favor of Medicare-for-all, increasing taxes on the wealthy, and remaking America's relationship with Saudi Arabia. Perhaps most important of all, he insisted that Democrats must do more than simply run against President Trump in 2020. He sounded smart, concise, and polished in a way that he rarely has, and managed to do so despite a hostile and occasionally moronic line of questioning — e.g., the usual "If you love taxes so much, why don't you marry them?" shtick.

Sanders's willingness to go into the lions' den shows that he already sees himself not as someone contending for the nomination of his party but rather as a de facto nominee pitching his ideas to the wider American public. This confidence puts him in a rhetorically advantageous position.

The Democratic National Committee's announcement in March that Fox News would not be allowed to host any debates with its candidates was cowardly. (It also side-stepped the fact that no network's talent tried harder to hold Trump to account during the last cycle of debates than Fox News' Megyn Kelly and Chris Wallace.) Sanders understands that he has nothing to lose and everything to gain by appearing in front of right-leaning audiences. On a channel where the top opinion program is hosted by Tucker Carlson, who has spoken positively about single-payer health care and criticized the financialization of the American economy, why shouldn't Democrats expect to reach people?

Because only one of them is Bernie. This is the key to his appeal and the path he will try to take toward the nomination in 2020. If 2016 showed us anything it is that in an overly crowded primary field one candidate who is able to distinguish himself clearly and immediately from the competition can win primaries. This will not be because he starts with the support of an overwhelming majority — much the opposite. But all Sanders needs is what Trump had last time, which is to say, a plurality of 25 or 30 percent. When you add up their 1 or 2 or 5 percent each, the other dozen or so candidates have more voters between them, but it counts for absolutely nothing.

There is one likely obstacle for Sanders and his outsider-plurality strategy going forward. This is the possibility that Democrats will line up behind a single establishment candidate whose chief virtue for many is that simply that he or she is not Sanders. This is what Republicans failed to do in 2016 when Jeb Bush, Marco Rubio, and John Kasich each in turn presented himself as the healthy consensus choice only to find themselves rejected by the party's base.

The most obvious person to fill this role in 2020 is, of course, Joe Biden, who has not even announced his candidacy yet. His attempt to apologize without apologizing for his handsy antics will please older voters, but it is unlikely to persuade the crucial but poorly understood bloc of younger Democrats who are socially liberal and fiscally moderate without explicitly acknowledging the latter — what I think of as the Refinery29 vote. Biden may not be an old white man with some icky misogynistic supporters like Sanders, but he still has too much baggage. There will always be as many arguments against him as there are for him, just as there were always enough reasons on hand for GOP primary voters to convince themselves not to get behind Jeb and Little Marco in 2016.

Sanders's political future is not assured. In addition to defining himself against the competition, he will require a certain amount of luck. The longer his fellow candidates remain in the race, the more successful his strategy is likely to be. The other lesson of the last election is one that he will probably remember — namely, that a radical outsider stands less of a chance running against one serious establishment candidate. Against the alphabet soup of O'RourkeWarrenButtigiegBookerKlobucharCastroYangGillibrandDelaneyGabbard he is Bernie. Against, say, Kamala Harris with the full backing of the DNC, he is, well, Bernie. That will make all the difference.